Apparatus for providing panoramic stereo image with single camera

ABSTRACT

An apparatus for providing a panoramic stereo image with a single camera is provided. The apparatus includes a first reflector reflecting panoramic surroundings viewed from a first viewpoint, a second reflector positioned to be coaxial with and separated from the first reflector to reflect panoramic surroundings viewed from a second viewpoint, and an image sensor positioned to be coaxial with the first and second reflectors to capture images respectively reflected by the first and second reflectors and output an image containing a first view and a second view. The apparatus provides a high three-dimensional recovery resolution, accomplishes compactness, and facilitates search of corresponding points in two images.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2005-0044467, filed on May 26, 2005, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for providing a panoramicstereo image needed to infer three-dimensional (3D) information using asingle camera, and more particularly, to an apparatus for providing apanoramic stereo image with a single camera, which provides a widestereo baseline, decreases its size, and facilitates correspondencesearch in a stereo image.

2. Description of the Related Art

Stereo vision systems using a camera are used to infer three-dimensional(3D) information from two images. In particular, panoramic stereosystems provide 3D information on a 360-degree panorama. Such systemscan be used in the field of 3D figure measurement, virtual reality,environment recognition of intelligent robots, monitoring andsurveillance systems, military detection systems, etc.

In panoramic stereo systems, 3D recovery is accomplished by identifyingparallax between two panoramic images obtained at two differentviewpoints. The two panoramic images can be obtained using two camerasor a single camera and mirrors. When two cameras are used, an error mayoccur during 3D recovery due to differences in physical characteristics,such as a difference in focal length and misalignment of imagingelements like a charge-coupled device (CCD) and a mirror, between thetwo camera systems. Accordingly, using a single camera stereo system isknown as more effective in various terms.

To easily implement a stereo vision system using a mirror, the shape ofthe mirror and a relative positional relationship between the mirror anda camera should satisfy a single viewpoint constraint. When thiscondition is not satisfied, it becomes complicated to extract 3Dinformation from two images. In particular, a plane mirror, anellipsoidal mirror, a hyperboloidal mirror, and a paraboloidal mirrorcan satisfy the condition of a single viewpoint constraint and support apanoramic system.

FIG. 1 is a conceptual diagram of a system using a hyperboloidal mirror100 among single-camera panoramic mono systems satisfying a singleviewpoint. An image of a 3D-space object 110 reflected by thehyperboloidal mirror 100 is projected on an image plane 130 of, forexample, a CCD via an effective pinhole 120 of a camera. The imagereflected by the hyperboloidal mirror 100 is the same as an image viewedfrom an effective viewpoint 140.

Meanwhile, conventional single-camera panoramic stereo systems areimplemented by placing a double-lobed mirror in front of a camera.However, a distance between effective viewpoints in the mirror is veryshort, and therefore, a depth resolution is very low. Moreover, anapparatus such as a robot requiring a single-camera panoramic stereosystem is demanded to be small. Accordingly, a single-camera panoramicstereo system suitable to compactness is desired. In addition, since twoimages obtained in a conventional single-camera panoramic stereo systemhave a resolution difference between corresponding points, ability tofind corresponding points in the two images may be decreased when theresolution of the obtained images is low. Therefore, a process ofcompensating for a resolution difference between the two images isdesired.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for providing a panoramicstereo image with a single camera, by which a distance between effectiveviewpoints is increased so that three-dimensional recovery resolution isincreased.

The present invention also provides an apparatus for providing apanoramic stereo image with a single camera and a folded mirror toaccomplish compactness.

The present invention also provides an apparatus for providing apanoramic stereo image with a single camera, by which correspondingpoints are easily detected even when there is a resolution differencebetween images obtained at two effective viewpoints, respectively.

According to an aspect of the present invention, there is provided anapparatus for providing a panoramic stereo image with a single camera.The apparatus includes a first reflector reflecting panoramicsurroundings viewed from a first viewpoint; a second reflectorpositioned to be coaxial with and separated from the first reflector toreflect panoramic surroundings viewed from a second viewpoint; and animage sensor positioned to be coaxial with the first and secondreflectors to capture images respectively reflected by the first andsecond reflectors and output a first image and a second image.

According to another aspect of the present invention, there is providedan apparatus for providing a panoramic stereo image with a singlecamera. The apparatus includes a first reflector reflecting panoramicsurroundings viewed from a first viewpoint, a second reflectorpositioned to be coaxial with and separated from the first reflector toreflect panoramic surroundings viewed from a second viewpoint, a thirdreflector positioned to be coaxial with the first and second reflectorsto reflect an image reflected by the second reflector, and an imagesensor positioned to be coaxial with the first, second and thirdreflectors to capture images respectively reflected by the first andthird reflectors and output a first image and a second image.

The apparatus may further include a panoramic image converter convertingthe first image and the second image provided from the image sensor togenerate a first panoramic image and a second panoramic image, and athree-dimensional position information extractor searching forcorresponding points in the first and second panoramic images andextracting three-dimensional position information from a positionaldifference between the searched corresponding points.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a conceptual diagram of a conventional panoramic mono systemusing a hyperboloidal mirror satisfying a single viewpoint constraint;

FIG. 2 is a block diagram of an apparatus for providing a panoramicstereo image with a single camera according to an embodiment of thepresent invention;

FIGS. 3A and 3B are conceptual diagrams of the arrangement of a cameraand mirrors according to an embodiment of the present invention;

FIGS. 4A through 4I are conceptual diagrams of the arrangement of amirror in a folded panoramic mono system satisfying the single viewpointconstraint;

FIGS. 5A through 5D are conceptual diagrams of the arrangement of acamera and a mirror in a folded-type apparatus for providing a panoramicstereo image with a single camera according to an embodiment of thepresent invention;

FIGS. 6A and 6B are conceptual diagrams of an image obtained in anembodiment of the present invention;

FIG. 7 is a photograph of an apparatus for providing a panoramic stereoimage with a single camera, which is implemented according to anembodiment of the present invention;

FIG. 8 illustrates an example of a captured omnidirectional stereo imageof an environment, which is obtained from an apparatus for providing apanoramic stereo image with a single camera, according to an embodimentof the present invention;

FIGS. 9A through 9C illustrate a higher view panoramic image, a lowerview panoramic image, and a disparity map, respectively, to which thepanoramic stereo image illustrated in FIG. 8 is converted; and

FIGS. 10A through 10C illustrate images including three-dimensionalinformation, which are recovered from the images illustrated in FIGS. 9Athrough 9C.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the attached drawings.

FIG. 2 is a block diagram of an apparatus for providing a panoramicstereo image with a single camera according to an embodiment of thepresent invention. The apparatus includes a first view provider 200, asecond view provider 210, an image sensor 220, a panoramic imageconverter 230, and a three-dimensional (3D) position informationextractor 240.

Each of the first view provider 200 and the second view provider 210reflects 360-degree surroundings viewed from an effective viewpoint totransfer a reflected image to the image sensor 220 like a charge-coupleddevice (CCD) of a camera. The first view provider 200 may include asingle reflector while the second view provider 210 includes one or tworeflectors. The shape and arrangement of the reflectors will bedescribed later. The term “reflector” used in this specificationindicates an object that reflects an image or a figure and usuallydenotes a mirror, but it is not restricted thereto in the presentinvention.

Two images reflected from the first and second view providers 200 and210, respectively, are projected onto the image sensor 220. The imagesensor 220 transmits a projected image to the panoramic image converter230. The projected image includes a central image and a peripheral imagewhich have a circle shape, which will be described later.

The panoramic image converter 230 converts the central image and theperipheral image, which are received from the image sensor 220, intopanoramic images, respectively. For the conversion, the correspondingposition in a circle-shape image for each position in a panoramic imageis sampled and mapped to the position in the panoramic image. Inparticular, positions in a circle-shape image corresponding to positionsin a panoramic image may be preset in a look-up table. The look-up tablein which positions in a circle-shape input image are respectively mappedto positions in a panoramic image can be implemented by analyzing thestructure of a camera-mirror system.

Meanwhile, when a resolution of the central image is different from thatof the peripheral image, the panoramic image converter 230 may include aresolution compensation function, which will be described later, inorder to facilitate search of corresponding points between two panoramicimages.

The 3D position information extractor 240 searches for correspondingpoints between the two panoramic images provided by the panoramic imageconverter 230 and extracts 3D position information such as distanceinformation of each object. Various methods including a window-basedcorrelation search method may be used to search for the correspondingpoints. In addition, various conventional techniques includingtriangulation may be used to extract 3D information.

FIGS. 3A and 3B are conceptual diagrams of the arrangement of a cameraand mirrors according to an embodiment of the present invention.

In the arrangement illustrated in FIG. 3A, a mirror without a bore isused. A first reflector 300 and a second reflector 310 have effectiveviewpoints F₁ and F₂, respectively, and reflect an object in 3D space.In other words, the first reflector 300 transfers a panoramic imageviewed from the effective viewpoint F₁ to the image sensor 220 of thecamera and the second reflector 310 transfers a panoramic image viewedfrom the effective viewpoint F₂ to the image sensor 220. The firstreflector 300 and the second reflector 310 correspond to the first viewprovider 200 and the second view provider 210, respectively, illustratedin FIG. 2. Meanwhile, to obtain both of a peripheral image and a centralimage, a reflective surface of the first reflector 300 must be smallerthan that of the second reflector 310.

In the arrangement illustrated in FIG. 3B, a mirror having a bore isused. The functions of a first reflector 320 and a second reflector 330are the same as those of the first and second reflectors 300 and 310illustrated in FIG. 3A. However, a path in which an image is projectedonto the image sensor 220 in the arrangement illustrated in FIG. 3B isdifferent from that in the arrangement illustrated in FIG. 3A and aperipheral image and a central image are the reverse of those obtainedin the arrangement illustrated in FIG. 3A. In other words, a centralimage is obtained from the first reflector 300 and a peripheral image isobtained from the second reflector 310 in the arrangement illustrated inFIG. 3A. In contrast, a central image is obtained from the secondreflector 330 and a peripheral image is obtained from the firstreflector 320 in the arrangement illustrated in FIG. 3B. Meanwhile, thediameter of the bore of the first reflector 320 is defined considering acurved surface thereof to obtain balanced peripheral and central images.

Through such arrangement of a camera and a mirror (i.e., througharranging two mirrors separate) and the shape of the mirror, a distancebetween the two effective viewpoints F₁ and F₂ can be increased. As aresult, a depth resolution can also be increased.

It will be satisfactory if each of the first reflectors 300 and 320 andeach of the second reflectors 310 and 330 are concave or convex mirrorsand are coaxial with each other. In addition, it is preferable that thesingle viewpoint constraint is satisfied in order to facilitateextraction of 3D information. In other words, a first reflector and asecond reflector may have a hyperboloid or ellipsoid and have theeffective viewpoints F₁ and F₂, respectively. In addition, asillustrated in FIG. 3B, the first reflector may have a bore. As aresult, there are 8 types of arrangement and shape of mirrors satisfyingthe single viewpoint constraint.

Alternatively, under the condition of the same stereo baseline (adistance between two effective viewpoints), folded type mirrors reducingan actual distance between mirror and an effective viewpoint may beused. In other words, when a mirror is added to the arrangementsillustrated in FIGS. 3A and 3B, a distance between the effectiveviewpoint F₂ and an effective pinhole P can be reduced under the sameeffective viewpoint distance (i.e., the same distance between theeffective viewpoints F₁ and F₂). As a result, the compactness of theapparatus can be accomplished. When an additional mirror is used, theapparatus can be smaller by folding an upper mirror to the vicinity ofthe height of a lens.

FIGS. 4A through 4I are conceptual diagrams of the arrangement of amirror in a folded panoramic mono system satisfying the condition of asingle viewpoint. In the drawings, PL, HYP, ELL, and PAR denote a planemirror, a hyperboloidal mirror, an ellipsoidal mirror, and aparaboloidal mirror, respectively. An image of an object in 3D space issequentially reflected by a first mirror and a second mirror and thenprojected onto an image plane. In other words, even though two mirrorsare used, one of the two mirrors just reflects an image reflected fromthe other mirror. As a result, the image sensor 220 obtains only oneimage (viewed from the effective viewpoint F₁). The relationship betweenthe two mirrors is referred to as a folded relationship. In particular,FIGS. 4A through 4I illustrate the shapes and arrangement of two mirrorsin the folded relationship satisfying the condition of a singleviewpoint. Such systems use a folded mirror as the second mirror so thata distance between the effective pinhole P and the effective viewpointF₁ can be reduced.

FIGS. 5A through 5D are conceptual diagrams of the arrangement of acamera and mirrors in a folded-type apparatus for providing a panoramicstereo image with a single camera according to an embodiment of thepresent invention. FIGS. 5A through 5D illustrate the topologies of thefolded relationship between each of second reflectors 505, 525, 545, and565 and each of third reflectors 510, 530, 550, and 570. The topologiesillustrated in FIGS. 5A through 5D use a topology illustrated in FIG. 4Ain common, but an hyperboloidal mirror is used for each of firstreflectors 500 and 540 illustrated in FIGS. 5A and 5C and an ellipsoidalmirror is used for each of first reflectors 520 and 560 illustrated inFIGS. 5B and 5D. Moreover, the first reflectors 500 and 520 are disposedat a central place in the topologies illustrated in FIGS. 5A and 5Bwhile the first reflectors 540 and 560 are disposed at an outer place inthe topologies illustrated in FIGS. 5C and 5D. In other words, each ofthe first reflectors 500, 520, 540 and 560 corresponds to the first viewprovider 200 illustrated in FIG. 2 and each of the second reflectors505, 525, 545, and 565 and each of the third reflectors 510, 530, 550,and 570 form a set corresponding to the second view provider 210illustrated in FIG. 2. Meanwhile, the diameter of a bore of a reflectoris defined considering a curved surface thereof to obtain a peripheralimage and a central image which are balanced with each other.

With respect to each of the nine topologies respectively illustrated inFIGS. 4A through 4I, four types of topologies illustrated in FIGS. 5Athrough 5D may be present. Consequently, there exist 36 types ofarrangement and shape of reflectors in a folded-type apparatus forproviding panoramic stereo images with a single camera according to thepresent invention.

For clarity of the description, the first reflectors 500, 520, 540 and560 are placed at the same heights as the third reflectors 510, 530,550, and 570, respectively, in FIGS. 5A through 5D, but the presentinvention is not restricted thereto. The first reflectors 500, 520, 540and 560 may be placed at different heights than the third reflectors510, 530, 550, and 570, respectively.

FIGS. 6A and 6B are conceptual diagrams of an image obtained in anembodiment of the present invention. Any panoramic stereo system havinga single camera and at least one reflector which are coaxial with eachother receives a stereo image through a central region and a peripheralregion, as illustrated in FIG. 6A. Such system is most advantageous inthat since all epipolar lines are simply placed in a radial shape, animage having a form illustrated in FIG. 6A can be easily converted intoa panoramic image having parallel epipolar lines.

Referring to FIG. 6A, r_(i) and r_(o) correspond to Φ. When surroundingshaving an effective viewpoint corresponding to a central image as anorigin are expressed in spherical coordinates (r,θ,Φ), r_(i) and Φ havea relationship defined by r_(i)=f(Φ). Similarly, when surroundingshaving an effective viewpoint corresponding to a peripheral image as anorigin are expressed in spherical coordinates (r,θ,Φ), r_(o) and Φ havea relationship defined by r_(o)=g(Φ). The functions f( ) and g( ) can beobtained from the shape of a reflector, i.e., a mirror.

In these stereo system, two images respectively obtained at twoeffective viewpoints have different resolutions. Accordingly, theperformance of the 3D information extractor 240 searching forcorresponding points in the two images may be decreased when theresolution of an image input to the panoramic image converter 230 is nothigh. For example, a resolution in a circular direction linearlydecreases from an outer radius of a circle to a center of the circle. Inaddition, a resolution in a radial direction may also differentaccording to the shape of a cross-section of the mirror.

To overcome these problems, the panoramic image converter 230 maycompensate for a resolution difference using a scale-space samplingstrategy. Resolution compensation can be accomplished when a Gaussiankernel G(s σ) along an x-axis and a y-axis in an image plotted in anorthogonal coordinate system is applied to an original image using anappropriate scale factor “s”. Here, G denotes a Gaussian kernel, and “σ”is a reference standard deviation of the Gaussian kernel and is set to aminimum value for reducing aliasing and noise. An image obtained whens=2 is used has double resolution than an image obtained when s=4. In anembodiment of the present invention using this principle, an appropriatescale factor is applied to each position (r_(i) or r_(o),θ) in each of acentral image and a peripheral image, whereby resolution compensation isaccomplished.

In an embodiment of the present invention, each of a first image and asecond image, which are provided in a circular shape from the imagesensor 220, is identified as a central image or a peripheral image.Next, G(s_(i) ^(r)σ) and G(s_(i) ^(c)σ) are applied to the central imagein a radial direction and a circular direction, respectively. Inaddition, G(s_(o) ^(r)σ) and G(s_(o) ^(c)σ) are applied to theperipheral image in a radial direction and a circular direction,respectively. Here, s_(i) ^(r), s_(o) ^(r), s_(i) ^(c), and s_(o) ^(c)are defined as${\max\left( {1,{\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}}} \right)},{\max\left( {1,{\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}}} \right)},1,\quad{{and}\quad\frac{r_{o}}{r_{i}}},$respectively, and “σ” is set to a minimum value for reducing aliasingand noise. In other words, an image to which a Gaussian kernel will beapplied is expressed in the circular direction (θ) and the radialdirection (r_(i) or r_(o)), and therefore, when a latitude Φ is given, ascale factor is defined with respect to the variables r_(i), r_(o), andθ. Here, subscripts “i” and “o” indicate “inner” and “outer” portions,respectively, and superscripts “r” and “c” indicate “radial” and“circular” directions, respectively. A Gaussian kernel for each ofpositions (r_(i) or Φ,θ) and (r_(o) or Φ,θ) are obtained by obtainings_(i) ^(r), s_(o) ^(r), s_(i) ^(c), and s_(o) ^(c).

The above-described resolution compensation is performed by thepanoramic image converter 230. In other words, the panoramic imageconverter 230 fundamentally converts two circular images illustrated inFIG. 6A into two panoramic images illustrated in FIG. 6B and may use amethod of sampling in each circular image with respect to each positionin a corresponding panoramic image for the conversion. To use theabove-described resolution compensation function, the following schememay be used first. The two circular images are identified as a centralimage and a peripheral image, respectively. A Gaussian kernel having astandard deviation${\max\left( {1,{\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}}} \right)}\sigma$in a radial direction and a standard deviation of σ in a circulardirection are applied to a position in the central image, whichcorresponds to a position in a panoramic image, and the result of theapplication is mapped to the position in the panoramic image. Similarly,a Gaussian kernel having a standard deviation${\max\left( {1,{\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}}} \right)}\sigma$in a radial direction and a standard deviation of$\frac{r_{o}}{r_{i}}\sigma$in a circular direction are applied to a position in the peripheralimage, which corresponds to a position in another panoramic image, andthe result of the application is mapped to the position in the panoramicimage. When the above-described operation is completely performed on allof positions in the two panoramic images, panoramic image conversionends. Here, a Gaussian kernel is applied as follows. On the basis of aposition (or a pixel) in a circular image corresponding to a position ina panoramic image, a central pixel and adjacent pixels are respectivelymultiplied by weights of Gaussian kernels corresponding to therespective pixels and the results of the multiplications are summed. Theresult of the summation is a intensity (brightness) information valuewith respect to the position in the panoramic image. Meanwhile,coordinate conversion from a circular image to a panoramic image ispossible in a cylindrical coordinate system as well as a sphericalcoordinate system. In other words, coordinate conversion is performed inthe same manner in both of the spherical coordinate system and thecylindrical coordinate system, with exception that Φ in the sphericalcoordinate system is changed into “z” in the cylindrical coordinatesystem.

FIG. 7 is a photograph of an apparatus for providing a panoramic stereoimage with a single camera, which is implemented according to anembodiment of the present invention. Here, a camera is positioned insidea lower mirror, which is implemented according to the topologyillustrated in FIG. 5C.

FIG. 8 illustrates an example of a captured omnidirectional stereo imageof an environmnet, which is obtained from an apparatus for providing apanoramic stereo image with a single camera, according to an embodimentof the present invention. A table and a robot in the vicinity of theapparatus and a desk and a shelf far away from the apparatus areprojected onto a central portion and a peripheral portion. Referring toFIG. 8, each pair of corresponding points between the central portionand the peripheral portion exist on the same radial line and thus theirepipolar lines also exist on the same radial line.

FIGS. 9A through 9C illustrate a higher view panoramic image, a lowerview panoramic image, and a disparity map, respectively, to which thepanoramic stereo image illustrated in FIG. 8 is converted. The disparitymap illustrated in FIG. 9C displays a difference between positions ofcorresponding points in the two panoramic images. In the disparity map,a brightness value is given in proportion to the magnitude of eachdifference. An object near the apparatus has a large positionaldifference according to a viewpoint and is thus expressed bright. Anobject far away from the apparatus has a small positional difference andis thus expressed dark. 3D information can be extracted from thedisparity map.

FIGS. 10A through 10C illustrate images including three-dimensionalinformation, which are recovered from the images illustrated in FIGS. 9Athrough 9C. An image illustrated in FIG. 10A is obtained at a viewpoint16-degree higher than a viewpoint of an image illustrated in FIG. 10Band an image illustrated in FIG. 10C is obtained at a viewpoint16-degree lower than the viewpoint of the image illustrated in FIG. 10B.All of the three images illustrated in FIGS. 10A through 10C can beobtained based on 3D position information extracted from the panoramicimages illustrated in FIGS. 9A and 9B.

According to the present invention, since a single camera is used, arecovery error caused by differences in physical characteristics betweena plurality of cameras can be reduced. In addition, since a plurality ofmirrors coaxial with the camera are used, epipolar lines between twoimages are located on the same line. As a result, a process of searchingfor corresponding points in two images is simplified. Moreover, adistance between effective viewpoints, which determines the accuracy of3D recovery, can be increased by separating the plurality of mirrors.The present invention uses a single camera and a folded-type system,thereby accomplishing compactness. An error occurring due to aresolution difference between a peripheral image and a central image canbe compensated for by using scale-space theory.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. An apparatus for providing a panoramic stereo image with a singlecamera, the apparatus comprising: a first reflector reflecting panoramicsurroundings viewed from a first viewpoint; a second reflectorpositioned to be coaxial with and separated from the first reflector toreflect panoramic surroundings viewed from a second viewpoint; and animage sensor positioned to be coaxial with the first and secondreflectors to capture images respectively reflected by the first andsecond reflectors and output an image containing a first view and asecond view.
 2. The apparatus of claim 1, wherein the first reflectorcomprises a hyperboloid or an ellipsoid as a reflecting surface, and thesecond reflector comprises as a reflecting surface a hyperboloid or anellipsoid having a bore with a predetermined diameter, which is coaxialwith the first reflector.
 3. The apparatus of claim 1, wherein thesecond reflector comprises a hyperboloid or an ellipsoid as a reflectingsurface, and the first reflector comprises as a reflecting surface ahyperboloid or an ellipsoid smaller than the reflecting surface of thesecond reflector.
 4. The apparatus of claim 1, further comprising: apanoramic image converter converting the first image and the secondimage provided from the image sensor to generate a first panoramic imageand a second panoramic image; and a three-dimensional positioninformation extractor searching for corresponding points in the firstand second panoramic images and extracting three-dimensional positioninformation from a positional difference between the searchedcorresponding points.
 5. The apparatus of claim 4, wherein the panoramicimage converter applies a Gaussian kernel having a standard deviation${\max\left( {1,{\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}}} \right)}\sigma$in a radial direction and a standard deviation of σ in a circulardirection to each position in a central image and maps the result of theapplication to a position in the first panoramic image, therebygenerating the first panoramic image, and applies a Gaussian kernelhaving a standard deviation${\max\left( {1,{\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}}} \right)}\sigma$in a radial direction and a standard deviation of$\frac{r_{o}}{r_{i}}\sigma$ in a circular direction to each position ina peripheral image and maps the result of the application to acorresponding position in the second panoramic image, thereby generatingthe second panoramic image.
 6. An apparatus for providing a panoramicstereo image with a single camera, the apparatus comprising: a firstreflector reflecting panoramic surroundings viewed from a firstviewpoint; a second reflector positioned to be coaxial with andseparated from the first reflector to reflect panoramic surroundingsviewed from a second viewpoint; a third reflector positioned to becoaxial with the first and second reflectors to reflect an imagereflected by the second reflector; and an image sensor positioned to becoaxial with the first, second and third reflectors to capture imagesrespectively reflected by the first and third reflectors and output animage containing a first view and a second view.
 7. The apparatus ofclaim 6, wherein the first reflector comprises as a reflecting surface ahyperboloid or an ellipsoid having a bore with a predetermined diameterat the coaxial line, and the second reflector and the third reflectorhave a folded relationship satisfying a single viewpoint.
 8. Theapparatus of claim 6, wherein the first reflector comprises ahyperboloid or an ellipsoid as a reflecting surface, the secondreflector and the third reflector have a folded relationship satisfyinga single viewpoint, and the third reflector has a bore with apredetermined diameter at the coaxial line.
 9. The apparatus of claim 6,further comprising: a panoramic image converter converting the firstimage and the second image provided from the image sensor to generate afirst panoramic image and a second panoramic image; and athree-dimensional position information extractor searching forcorresponding points in the first and second panoramic images andextracting three-dimensional position information from a positionaldifference between the searched corresponding points.
 10. The apparatusof claim 9, wherein the panoramic image converter applies a Gaussiankernel having a standard deviation${\max\left( {1,{\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}}} \right)}\sigma$in a radial direction and a standard deviation of a in a circulardirection to each position in a central image and maps the result of theapplication to a position in the first panoramic image, therebygenerating the first panoramic image, and applies a Gaussian kernelhaving a standard deviation${\max\left( {1,{\frac{\mathbb{d}r_{o}}{\mathbb{d}\phi}/\frac{\mathbb{d}r_{i}}{\mathbb{d}\phi}}} \right)}\sigma$in a radial direction and a standard deviation of$\frac{r_{o}}{r_{i}}\sigma$ in a circular direction to each position ina peripheral image and maps the result of the application to a positionin the second panoramic image, thereby generating the second panoramicimage.